Production Data as an Indicator of Gas Reservoir Heterogeneity in the Vicksburg S Sandstones (Oligocene), McAllen Ranch Field, Hidalgo County, Texas: ABSTRACT

Exponential decline curve analysis is widely used to estimate recoverable reserves due to its simplicity. In most cases, however, an exponential model cannot provide a satisfactory match of overall production history. The generalised form of a hyperbolic decline model is more powerful in matching production history than the other decline models, but it is difficult to apply in practical production data analysis since it requires predicting two unknowns as decline constants. Although a hyperbolic model may provide a good fit to early-time production decline data; it may overestimate the late-time production, especially for hydraulic fractured wells in a tight-gas reservoir. In fact, the exponential decline model might be more reliable for forecasting the late-time production. This paper presents a practical approach to production decline analysis for non-fractured and fractured wells in a tight-gas reservoir using numerical simulation. Some production rate functions and type curves are introduced to obtain the best matching values of hyperbolic, exponential and harmonic production decline constants. The simulated production rate decline data for various well and reservoir parameters are used to indicate the optimum time duration of use of each decline model and to show the time when the production decline starts following the exponential model. The proposed approach is applied in production data analysis and forecasting for a tight-gas field in WA. The results showed good agreement with the production forecast obtained from a reservoir simulation.

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The Productivity Analysis in Tight Gas Reservoir by Using wire-line Logging and trial production Data

Procedia Engineering ◽

10.1016/j.proeng.2012.01.986 ◽

2012 ◽

Vol 31 ◽

pp. 29-37

Author(s):

Wenming Wu ◽

Yu Yang ◽

Xin Liu ◽

Taotao Luo ◽

Zong Dai

Keyword(s):

Production Data ◽

Tight Gas ◽

Productivity Analysis ◽

Gas Reservoir ◽

Tight Gas Reservoir

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Characterization of oil and gas reservoir heterogeneity

10.2172/7244979 ◽

1992 ◽

Cited By ~ 1

Author(s):

N. Tyler ◽

M.D. Barton ◽

D.G. Bebout ◽

R.S. Fisher ◽

J.D. Grigsby ◽

...

Keyword(s):

Oil And Gas ◽

Gas Reservoir ◽

Reservoir Heterogeneity ◽

Oil And Gas Reservoir

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Dynamic Material Balance Method for Estimating Gas in Place of Abnormally High-Pressure Gas Reservoirs

Lithosphere ◽

10.2113/2021/6669012 ◽

2021 ◽

Vol 2021 (Special 1) ◽

Author(s):

Lixia Zhang ◽

Yingxu He ◽

Chunqiu Guo ◽

Yang Yu

Keyword(s):

High Pressure ◽

Material Balance ◽

Balance Method ◽

Production Data ◽

Reservoir Pressure ◽

Material Balance Equation ◽

Gas Reservoirs ◽

Gas Reservoir ◽

Material Balance Method ◽

The Relationship

Abstract Determination of gas in place (GIP) is among the hotspot issues in the field of oil/gas reservoir engineering. The conventional material balance method and other relevant approaches have found widespread application in estimating GIP of a gas reservoir or well-controlled gas reserves, but they are normally not cost-effective. To calculate GIP of abnormally pressured gas reservoirs economically and accurately, this paper deduces an iteration method for GIP estimation from production data, taking into consideration the pore shrinkage of reservoir rock and the volume expansion of irreducible water, and presents a strategy for selecting an initial iteration value of GIP. The approach, termed DMBM-APGR (dynamic material balance method for abnormally pressured gas reservoirs) here, is based on two equations: dynamic material balance equation and static material balance equation for overpressured gas reservoirs. The former delineates the relationship between the quasipressure at bottomhole pressure and the one at average reservoir pressure, and the latter reflects the relationship between average reservoir pressure and cumulative gas production, both of which are rigidly demonstrated in the paper using the basic theory of gas flow through porous media and material balance principle. The method proves effective with several numerical cases under various production schedules and a field case under a variable rate/variable pressure schedule, and the calculation error of GIP does not go beyond 5% provided that the production data are credible. DMBM-APGR goes for gas reservoirs with abnormally high pressure as well as those with normal pressure in virtue of its strict theoretical foundation, which not only considers the compressibilities of rock and bound water, but also reckons with the changes in production rate and variations of gas properties as functions of pressure. The method may serve as a valuable and reliable tool in determining gas reserves.

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